In an existing heads up display, information is projected onto a specially treated portion of the windshield and reflected into the eyes of the driver. An important component of a head-up display system is known as the combiner. The combiner is positioned forward of the driver and extends partly across his or her view of the real world scene. It is usually either on the interior surface of or laminated inside of the windshield. It is constructed to transmit light from the real world scene ahead of the vehicle and to reflect light information of one or more particular wavelengths propagating from a source within the vehicle. The information is projected onto the combiner using suitable optical elements. The light rays reflected by the combiner are typically collimated to present an image of the information focused at optical infinity permitting the driver to simultaneously view the real world scene and the displayed information without changing eye focus.
Some combiners are simply semi-reflecting mirrors while a particularly effective combiner can be constructed using a hologram or a holographic optical element. In a currently used heads up display in motor vehicles, the motorist views the forward outside real world scene through the windshield. Information pertaining to the operational status of the vehicle is displayed on a heads up display system providing vehicle information, such as fuel supply and vehicle speed, positioned within the motorist's field of view through the windshield thereby permitting the motorist to safely maintain eye contact with the real world scene while simultaneously viewing the display of information. However, such heads up displays are not interactive.
Heads up displays are widely used on airplanes particularly military airplanes. Although many attempts have been made to apply this technology to automobiles, as yet few heads up display systems are on production vehicles. Nevertheless, it is anticipated that more such systems will appear on vehicles in the near future. One reason that heads up displays have not been widely implemented is that vehicle operators have not been willing to pay the cost of such a system merely to permit the operator to visualize his speed or the vehicle temperature, for example, without momentarily taking his eyes from the road. In other words, the service provided by such systems is not perceived to be worth the cost.
There are functions other than viewing the vehicle gages that a driver typically performs that require significantly more attention than a momentary glance at the speedometer. Such functions have heretofore not been considered for the heads up display system. These functions are primarily those functions that are only occasionally performed by the vehicle operator and yet require significant attention. As a result, the vehicle operator must remove his eyes from the road for a significant time period while he performs these other functions creating a potential safety problem. One example of such a function is the adjustment of the vehicle entertainment system. The vehicle entertainment system has become very complex in modern automobiles and it is now very difficult for a vehicle driver to adjust the system for optimum listening pleasure while safely operating the vehicle.
Other similar functions include the adjustment of the heating, ventilation, air conditioning and defrosting system, the dialing and answering of cellular phone calls, as well as other functions which are contemplated for future vehicles such as navigational assistance, Internet access, in-vehicle messaging systems, traffic congestion alerts, weather alerts, etc. Each of these functions, if performed by a driver while operating the vehicle, especially under stressful situations such as driving on congestion highways or in bad weather, contribute an unnecessary risk to the driving process. While a driver is attempting to operate the vehicle in a safe manner, he or she should not be required to remove his or her eyes from the road in order to adjust the radio or make a phone call. Therefore, the purpose of this invention is to minimize this risky behavior by permitting the operator to perform these functions without taking his or her eyes off of the road. As discussed in greater detail below, this is accomplished through the use of a heads up display system combined with a touch pad located, for example, at the center of the steering wheel within easy reach of the driver, or a voice input system.
Prior Art Related to Heads Up Display Systems
There are many patents and much literature that describe the prior art of heads up displays. Among the most significant of the patents are:
U.S. Pat. No. 4,218,111 which describes a lens system for one of the early holographic heads up display units.
U.S. Pat. No. 4,309,070 which describes an aircraft head up display system for pilots.
U.S. Pat. No. 4,613,200 which describes a system for using narrow wavelength bands for the heads up display system. It describes a rather complicated system wherein two sources of information are combined. This patent is believed to be the first patent teaching a heads up display for automobiles.
U.S. Pat. No. 4,711,544 which describes a head up display for an automobile and clearly describes the process by which the focal length of the display is projected out front of the automobile windshield. In this manner, the driver does not have to focus on a display which is close by as, for example, on the instrument panel. Thus, the driver can continue to focus on the road and other traffic while still seeing the heads up display.
U.S. Pat. No. 4,763,990 which describes a method for reducing flare or multiple images resulting in a substantially aberration free display. This is a problem also discussed by several of the other prior art patents.
U.S. Pat. No. 4,787,040 which describes another type display system for automobiles which is not a heads up display. This patent shows the use of “an infrared touch panel or Mylar(™) touch switch matrix mounted over the face of the display”.
U.S. Pat. No. 4,787,711 which describes and solves problems of double reflection or binocular parallax that results from conventional heads up displays for use in automobiles.
U.S. Pat. No. 4,790,613 which presents a low-cost heads up display with fixed indicia. The message is fixed but displayed only as needed.
U.S. Pat. No. 4,886,328 which shows a heads up display device and describes a method for preventing damage to the optics of the system caused by sunlight.
U.S. Pat. No. 4,973,132 which describes a polarized holographic heads up display which provides for increased reflectivity and image contrast.
U.S. Pat. No. 5,013,135 which describes a heads up display using Fresnel lenses to reduce the space required for installation of the system.
U.S. Pat. No. 5,157,549 which describes another method of reducing the damage to the heads up display optics by restricting the wavelengths of external light which are reflected into the heads up display optics.
U.S. Pat. No. 5,210,624 which describes a heads up display wherein all light from the environment is allowed to pass through the combiner except light having a frequency equal to the frequency generated by the heads up display. The alleged improvement is to also filter out light from the environment that is of a complementary color to the light from the heads up display.
U.S. Pat. No. 5,212,471 which describes a method for reducing the reflections from the outside windshield surface which produces ghost images.
U.S. Pat. No. 5,229,754 which describes apparatus for increasing the path length of the heads up display using a reflecting plate. This improves the quality of the heads up display while maintaining a compact apparatus design. This added travel of the light rays is needed since in this system the virtual image is located as far in front of the vehicle windshield as the distance from the information source to the heads up display reflector.
U.S. Pat. No. 5,231,379 which describes a method for compensating for the complex aspheric curvature of common windshields. It also provides means of adjusting the vertical location of the reflection off the windshield to suit the size of a particular driver or his preferences.
U.S. Pat. No. 5,243,448 which describes a low-cost heads up display for automobiles.
U.S. Pat. No. 5,289,315 which describes apparatus for displaying a multicolored heads up display. The technique uses two films having different spectral reflectivities.
U.S. Pat. No. 5,313,292 which describes a method for manufacturing a windshield containing a holographic element. This patent presents a good description of a heads-up display unit including mechanisms for reducing the heat load on the LCD array caused by the projection lamp and means for automatically adjusting the intensity of the heads up display so that the contrast ratio between the heads up display and the real world is maintained as a constant.
U.S. Pat. No. 5,313,326 which describes a heads up display and various methods of improving the view to drivers looking at the heads up display from different vertical and lateral positions. The inventor points out that “ . . . the affective eye box presented to the driver, i.e. the area within which he will be able to see the image is inherently limited by the effective aperture of the optical projection unit”.
The inventor goes on to teach that the eye box should be as large as possible to permit the greatest tolerance of the system to driver height variation, driver head movement, etc. It is also desirable to have a compact optical projection system as possible since available space in the car is limited. There are, however, limitations on the length of the projection unit and the size of the eye box that is achievable.
First, while the use of more powerful optics will permit a shorter physical length unit for a fixed image projection distance, this will give a higher display magnification. The higher the magnification, the smaller the actual display source for a specific image size. Display resolution then becomes a critical factor. A second limitation of optical systems is that for a given eye box a shorter focal length system cannot achieve as good an image quality as a long focal length system.
U.S. Pat. No. 5,329,272, as well as many of the other patents cited above, which describes the use of a heads up display to allow the operator or driver to watch the speedometer, revolution counter, directional indicators, etc. while keeping his or her eyes on the road. This patent is concerned with applying or adapting a large bulky optical system to the vehicle and solves problem by placing the main elements of this optical system in a direction parallel to the transverse axis of the vehicle. This patent also describes a method for adjusting the heads up display based on the height of the driver. It mentions that using the teachings therein that the size of the driver's binocular or eye box is 13 cm horizontal by 7 cm vertical.
U.S. Pat. No. 5,379,132 which attempts to solve the problem of the limited viewing area provided to a driver due to the fact that the size of the driver is not known. A primary object of the invention is to provide a display having an enlarged region of observation. This is done by reducing the image so that more information can be displayed on the heads up display.
U.S. Pat. No. 5,414,439 which states that such heads up displays have been quite small relative to the roadway scene due to the limited space available for the required image source and projection mirrors.
U.S. Pat. No. 5,422,812 which describes an in route vehicle guidance system using a heads up display, but not one that is interactive.
U.S. Pat. No. 5,486,840 which describes a heads up display which purportedly eliminate the effect where sunlight or street lights travel down the path of the heads up display optics and illuminate the projection surface and thereby cause false readings on the heads up display. This problem is solved by using circularly polarized light.
U.S. Pat. No. 5,473,466 describes a miniature high resolution display system for use with heads up displays for installation into the helmets of fighter pilots. This system, which is based on a thin garnet crystal, requires very little power and maintains a particular display until display is changed. Thus, for example, if there is a loss of power the display will retain the image that was last displayed. This technology has the capability of producing a very small heads up display unit as will be described more detail below.
U.S. Pat. No. 5,812,332 which describes a windshield for a head up display system that reduces the degree of double imaging that occurs when a laminated windshield is used as the combiner in the display system.
U.S. Pat. No. 5,859,714 which describes a method for making the combiner such that a colored heads up display can be created.
Finally, U.S. Pat. No. 5,724,189 which describes methods and apparatus for creating aspheric optical elements for use in a heads up display.
All of the above patents are included herein in their entirety by reference.
Summary of the Heads Up Prior Art:
All of the heads up display units described are for providing an alternate to viewing the gages on the instrument panel or at most the displaying of a map. That is, all are passive systems. Nowhere has it been suggested in the above-mentioned prior art to use the heads up display as a computer screen for interactive use by the vehicle operator where the driver can operate a cursor and/or otherwise interact with the display.
No mention is made in the above-mentioned prior art of the use of a heads up display for: the Internet; making or receiving phone calls; compartment temperature control; control of the entertainment system; active route guidance with input from an external source such as OnStar™; in vehicle signage; safety alerts; weather alerts; traffic and congestion alerts; video conferencing; TV news broadcasts; display of headlines, sports scores or stock market displays; or of switches that can be activated orally or by a touch pad in the center of the steering wheel or elsewhere.
Furthermore, there does not appear to be any examples of where a heads up display is used for more than one purpose, that is, where a variety of different pre-selectable images are displayed.
Background on Touch Pad Technologies
Touch pads are closely related to their “cousins”, touch screens. Both use the operator's fingers as the direct link between the operator and the computer. In some cases, a stylus is used but not for the cases to be considered here. In simple cases, touch pads can be used to operate virtual switches and, in more complicated cases, the movement of the operators finger controls a cursor, which can be used to select from a range of very simple to very complicated functions. Several technologies have evolved which will now be described along with some of their advantages and shortcomings.
Capacitive touch pads use the electrical (conductive and dielectric) properties of the user's finger as it makes contact with the surface of the pad. This capacitive technology provides fast response time, durability and a tolerance for contamination. Generally, grease, water and dirt will not interfere with the operation of the capacitive touch pad. Unfortunately, this technology will not work well for steering wheel applications, for example, when the driver is wearing gloves.
Projected capacitive touch pads sense changes in the electrical field adjacent the touch pad. This technology will work with a driver wearing gloves but does not have as high a resolution as the standard capacitive touch pads.
Infrared touch pads contain a grid of light beams across the surface of the pad and check for interruptions in that grid. This system is somewhat sensitive to contamination that can block the transmitters or receivers.
Surface acoustic wave (SAW) touch pads send sound waves across the surface of the touch pad and look for interruptions or damping caused by the operator's fingers. This technology requires the use of a rigid substrate such as glass that could interfere with the operation of the airbag deployment door. It is also affected by contaminants which can also absorb the waves.
Guided acoustic wave technology is similar to SAW except that it sends the waves through the touch pad substrate rather than across the surface. This technology also requires a rigid substrate such as glass. It is additionally affected by contamination such as water condensation.
Force sensing touch pads measure the actual force placed on the pad and is measured where the pad is attached. Typically, strain gages or other force measuring devices are placed in the corners of a rigid pad. This technology is very robust and would be quite applicable to steering wheel type applications, however, it generally has less resolution than the other systems. Force sensing touch pads are either strain gage or platform types. The strain gage touch pad measures the stresses at each corner that a touch to the pad creates. The ratio of the four readings indicates the touch point coordinates. The platform touch pad instead rests on a platform with force measurement sensors at the supports. A touch onto the touch pad translates to forces at the supports.
Resistive touch pads use a flexible resistive membrane, a grid of insulators and a secondary conducting pad to locate the touch point. This pad generally has higher resolution than the force sensing touch pads and is equally applicable to steering wheel type applications. A further advantage is that it can be quite thin and does not generally require a rigid substrate which can interfere with the deployment of the airbag door. Resistive technology touch screens are used in more applications than any other because of the high accuracy fast response and trouble-free performance in a variety of harsh applications.
There are many U.S. patents and other publications that describe touch pad technologies primarily as they relate to inputting data into a computer. Among the significant patents are:
U.S. Pat. No. 4,190,785 which describes a touch pad using a piezoelectric layer. When a finger pressure is placed on the piezoelectric, a voltage is generated. The touch pad actually consists of an array of sensors rather than a continuously varying sensing element. One advantage of the system is that it can be passive. The piezoelectric coating is approximately 0.005 inches thick.
U.S. Pat. No. 4,198,539 which describes a touch pad based on resistance. Through a novel choice of resistors and uniform resistive pad properties, the inventor is able to achieve a uniform electric field in the resistance layer of the touch pad.
U.S. Pat. No. 4,328,441 which describes a “piezoelectric polymer pressure sensor that can be used to form a pressure sensitive matrix keyboard having a plurality of keyboard switch positions arranged in a plurality of rows and columns”. The piezoelectric electric polymer film is made from polyvinylidene fluoride. This is only one example of the use of the piezoelectric polymer and some others are referenced in this patent. This touch pad is set up as a series of switches rather than a continuous function.
U.S. Pat. No. 4,448,837 which describes the use of a silicone rubber elastic sheet which has been partially filled with conductive particles of various sizes as part of a resistive touch pad.
U.S. Pat. No. 4,476,463 which describes a touch pad system for use as an overlay on a display that can detect and locate a touch at any location anywhere on the display screen. In other words, it is a continuously variable system. This system is based on a capacitive system using an electrically conductive film overlaying the display screen.
U.S. Pat. No. 4,484,179 which describes a touch sensitive device which is at least partially transparent to light. A flexible membrane is suspended over a CRT display and when pushed against the display it traps light emitted at the contact point by the scanning system. This trapped light can be sensed by edge mounted sensors and the position of the touch determined based on the known position of the scan when the light was detected.
U.S. Pat. No. 4,506,354 which describes an ultrasonic touch pad type device wherein two ultrasonic transducers transmit ultrasound through the air and receive echoes based on the position of a finger on the touch pad.
U.S. Pat. No. 4,516,112 which describes another implementation of a touch pad using a piezoelectric film.
U.S. Pat. No. 4,633,123 which describes another piezoelectric polymer touch screen, in this case used as a keyboard apparatus.
U.S. Pat. Nos. 4,745,301 and 4,765,930 which describe a deformable pressure sensitive electroconductive switch using rubber which is loaded with conductive particles and which could be used in a touch switch or touch pad configuration.
U.S. Pat. No. 4,904,857 which describes a touch screen based on light emitting diodes (LEDs) and receptors wherein light beams are sent parallel to and across the top of the video screen and the interruption of these light beams is sensed.
U.S. Pat. No. 4,963,417 which describes a touch pad consisting of a conductive layer and a layer of deformable insulating particles and a conductive film layer. Pressure on the conductive film layer causes the insulating deformable particles to deform and permits contact between the conductive film and the conductive substrate that can be sensed by resistant measurements.
U.S. Pat. No. 4,964,302 which describes a tactile sensor which can be used by robots for example. The tactile sensor consists of a series of ultrasonic pads and a deformable top layer. When the deformable layer is compressed, the compression can be sensed by the time of flight of the ultrasonic waves by the ultrasonic sensor and therefore both the location of the compression can be determined and the amount compression or force. Such an arrangement is applicable to the touch pads of the current invention as described below. This permits an analog input to be used to control the radio volume, heating or air conditioning temperature, etc.
U.S. Pat. No. 5,008,497 which describes an accurate means for measuring the touch position and pressure on a resistive membrane.
U.S. Pat. No. 5,060,527 which is another example of the tactile sensor that is capable of measuring variable force or pressure. This patent uses an electrically conductive foam as the variable resistance that permits force to be measured.
U.S. Pat. No. 5,159,159 which is another example of a touch pad that is based on resistance and provides the X and Y position of the finger and the pressure at the touch point.
U.S. Pat. No. 5,164,714 which is another system using light emitters and detectors creating a field of light beams going across the surface of the touch pad in both X and Y directions.
U.S. Pat. No. 5,374,449 which describes a monolithic piezoelectric structural element for keyboards which can be used to form discrete switching elements on the pad.
U.S. Pat. No. 5,376,946 which describes a touch screen made of two transparent conductive members which when caused to contract each other change the resistance of the circuit such that, by alternately applying a voltage to the X and Y edges, the location of the touch point can be determined.
A capacitive based touch screen is illustrated in U.S. Pat. No. 5,386,219.
U.S. Pat. No. 5,398,962 which describes a horn activator for steering wheels with airbags. This horn activator switch can be made part of the touch pad as discussed below whereby when the pressure exceeds a certain amount, a horn blows rather than or in addition to activating the heads up display.
U.S. Pat. No. 5,404,443 which describes a CRT display with a touch pad overlay for use in an automobile.
U.S. Pat. No. 5,453,941 which describes a touch pad of the resistive type which also measures pressure as well as location of the touch. This patent uses two separate boards, one for the X coordinate and one for the Y coordinate. A pressure applied against the point located on the X coordinate resistance board causes the X coordinate resistance board to make contact with the Y coordinate resistance board at a point located on the Y coordinate resistance board. The contact is through a contact resistance the magnitude of which is inversely proportional to the pressure applied.
U.S. Pat. No. 5,518,078 which is another example were separate films are used for the X and Y direction. Voltages are selectively applied to the film for measuring the X coordinate and then to the film for measuring the Y coordinate. The pressure of the touch is determined by the contact resistance between the X and Y films.
Most of the prior art devices described above have an analog input, that is, the resistance or capacitance is continuously varying as the pressure point moves across the pad. U.S. Pat. No. 5,521,336, on the other hand, describes a touch pad which provides a digital input device by using sets of parallel strips in one layer orthogonal to another set of parallel strips in another layer. Upon depressing the surface, the particular strips which make contact are determined. These are known as high-density switch closure type touch pad sensors.
U.S. Pat. No. 5,541,372 which describes the use of strain gages to detect deformation of the touch panel itself as result of force being applied. Strain gages are physically integrated with the panel and measure the strain on the panel. An important feature of the invention of this patent is that it measures the deformation of panel itself instead of the deformation of the suspension members of the panel as in the prior art.
U.S. Pat. No. 5,541,570 which describes a force sensing ink that is used in U.S. Pat. No. 5,563,354 to form a thin film force sensors to be used, for example, for horn activation.
U.S. Pat. No. 5,673,041 which describes a reflective mode ultrasonic touch sensitive switch. A touch changes the reflectivity of a surface through which the ultrasound is traveling and changes the impedance of the transducer assembly. This switch can be multiplied to form a sort of digital touch pad. A piezoelectric polymer film is used presumably to maintain the transparency of the switch.
U.S. Pat. No. 5,673,066 which relates to a coordinate input device based on the position of a finger or pen to a personal computer. This patent provides various means for controlling the motion of a cursor based on the motion of a finger and also of providing a reliable switching function when an item has been selected with the cursor. The invention describes the use of touch pressure to indicate the speed with which the cursor should move. A light touch pressure provides for a rapid movement of cursor whereas a strong touch pressure signifies a slow movement. The pressure on the touch pad is determined using four piezoelectric elements for converting pressures to voltages that are arranged on the four corners of the back surface of the rigid plate.
U.S. Pat. No. 5,686,705 which describes a touch pad consisting of a conductive surface containing three electrodes, a compressible insulating layer and a top conductive layer such that when the top conductive layer is depressed it will receive signals from the three electrodes. These signals are transmitted in pairs thereby permitting the location of the contact point on a line bisecting the two electrodes, then by using another pair, a second line can be determined and the intersection of those two lines fixes the point. The determination is based on the level of signal that is inversely proportional to the resistance drop between the contact point in the transmission point.
U.S. Pat. No. 5,917,906 which describes an alternate input system with tactile feedback employing the use of snap domes arranged in the predetermined spaced apart arrangement.
U.S. Pat. No. 5,933,102 which describes an array of capacitive touch switches.
U.S. Pat. No. 5,942,733 which describes a capacitive touch pad sensor capable of being actuated with a stylus input. The consists of a plurality of first parallel conductive traces running in the X direction and a plurality of second parallel conductive traces running in the Y direction. A layer of pressure conductive material is disposed over one of the faces of the substrate which in turn is covered with a protective layer. As the conductive later is moved toward the arrays of substrates the capacitance between the conductive later and each of the substrates is changed which is measurable. A capacitive touch pad has the advantage that it requires much less force than a resistive touch pad. The traces are actually put on both sides of substrate with the X traces going one way and Y traces the other way. An alternative would be to use a flex circuit.
International Patent Publication No. WO98/43202 which describes a button wheel pointing device for use with notebook personal computers.
International Publication No. WO98/37506 reserves various parts of the touch pad for command bar or scroll bar functions.
U.S. Pat. No. 5,374,787 which describes a two-dimensional capacitive sensing system equipped with a separate set of drive and sense electronics for each row and column of the capacitive tablet. The device capacitively senses the presence of the finger and determines its location. This concept is further evolved in U.S. Pat. Nos. 5,841,078, 5,861,583, 5,914,465, 5,920,310 and 5,880,411. U.S. Pat. No. 5,841,078 makes use in one embodiment of a neural network to interpret situations when more than one finger is placed on the touch pad. This allows the operator to use multiple fingers, coordinated gestures etc. for complex interactions. The traces can be placed on a printed circuit board or on a flex circuit. The sensor also measures finger pressure.
U.S. Pat. No. 5,861,583 which provides a two-dimensional capacitive sensing system that cancels out background capacitance effects due to environmental conditions such as moisture
Other capacitive prior art U.S. patents include U.S. Pat. Nos. 5,305,017, 5,339,213, 5,349,303 and 5,565,658. These patents also cover associated apparatus for capacitive touch pads sensors.
U.S. Pat. No. 5,565,658 which describes a system that can be used with gloves since the finger need not contact the surface of the touch pad and also describes a technique of making the touch pad using silk screening and a variety of inks, some conducting some non-conducting. The resulting array is both thin and flexible that allows it to be formed into curved surfaces such as required for a steering wheel mounted touch pad.
U.S. Pat. No. 5,940,065 which describes a mapping method of how to compensate for systematic and manufacturing errors which appear in a resistive touch sensor pad.
U.S. Pat. No. 5,694,150 which provides a graphical user interface system to permit multiple users of the same system. Such a system would be applicable when both the driver and passenger are viewing the same output on different heads up or other displays. This could also be useful, for example, when the passenger is acting as the navigator indicating to the driver on the heads up display where he is now and where he should go. Alternately, the navigator could be a remote access operator giving directions to the driver as to how to get to a specific location.
Touch pads that are commercially available include, for example, model TSM946 as supplied by Cirque Corporation and others supplied by the Elo and Synaptics corporations.
A human factors study has shown that the ideal size of the square target for the 95 percentile male population should be about 2.4 cm by 2.4 cm as reported in “A Touch Screen Comparison Study: Examination Of Target Size And Display Type On Accuracy And Response Time” by S. Gregory Michael and Michael E. Miller, Eastman Kodak Co. Rochester, N.Y.
Summary of the Touch Pad Prior Art
As can be appreciated from the sampling of touch pad patents and publications listed above, many technologies and many variations are available for touch pad technology. In particular, most of these designs are applicable for use, for example, as a touch pad mounted in the center of a steering wheel in accordance with the invention, as discussed more fully below. In general, the resolution required for a touch pad for a steering wheel application probably does not have to be as high as the resolution required—for entering drawing or map data to a computer database, for example. A vehicle driver is not going to be able to focus intently on small features of the display. For many cases, a few switch choices is all that will be necessary. This would allow the driver to use the first screen to select among the major function groups that he or she is interested in, which might comprise the entertainment system, navigation system, Internet, telephone, instrument panel cluster, and perhaps one or two additional subsystems. Once he or she selects the system of interest by pressing a virtual button, he or she would then be presented with a new display screen with additional options. If the entertainment system had been chosen, for example, the next series of what choices would include radio, satellite radio, Internet radio, TV, CD, etc. Once the choice among these alternatives has been selected the new screen of button choices would appear.
For other more involved applications, actual control of cursor might be required in much the same way that a mouse is used to control the cursor on a personal computer. In fact, the heads up display coupled with the steering wheel mounted touch pad can in fact be a personal computer display and control device. The particular choice of system components including the heads up display technology and the touch pad technology will therefore depend on the sophistication of the particular system application and the resulting resolution required. Therefore, essentially all of the technologies described in the above referenced prior art touch pad patents are applicable to the invention to be described herein. Therefore, all of the above patents are included herein in their entirety by reference.
Generally, the steering wheel mounted touch pad and heads up display system will result in safer driving for the vehicle operator. This is because many functions that are now performed require the driver to take his or her eyes from the road and focus on some other control system within the vehicle. With the system of this invention, this will not be necessary. On the other hand, the potential exists for adding many more functions, some of which may become very distracting. It is envisioned, therefore, that implementation of the system will be in stages and to a large degree will be concomitant with the evolution of other safety systems such as autonomous vehicles. The first to be adopted systems will likely be relatively simple with low resolution screens and minimum choices per screen. Eventually, full-length movies may someday appear on the heads up display for the entertainment of the vehicle operator while his vehicle is being autonomously guided.
The preferred touch pad technologies of those listed above include capacitance and resistance technologies. Most of the capacitance technologies described require the conductivity of the operator's finger and therefore will not functions if the driver is wearing gloves. Some of the patents have addressed this issue and with some loss of resolution, the standard capacitive systems can be modified to sense through thin driving gloves. For thicker gloves, the projected capacitive systems become necessary with an additional loss of resolution. It is contemplated in the invention described herein, that a combination of these technologies is feasible coupled with a detection system that allows the driver to adjust the sensitivity and thus the resolution of the capacitance system.
Resistance sensitive systems are also applicable and may also require the resolution adjustment system to account for people wearing heavy gloves.
Both the capacitance and resistance systems described in the above patents and publications usually have at least one rigid surface that forms the touch pad base or support. For applications on the center of the steering wheel, provision must be made for the airbag cover to open unimpeded by either the mass or strength of the touch pad. This is a different set of requirements than experienced in any of the prior art. This requires, for example, with the use of the capacitive system, that thin flexible circuits be used in place of rigid printed circuit boards. In the case of the resistive system, thin resistive pressure sensitive inks will generally be used in place of thicker variable resistance pads. Thin metal oxide films on thin plastic films can also be used, however, the durability of this system can be a serious problem.
Force sensing systems also require that the member upon which the force is applied be relatively rigid so that the force is transmitted to the edges of the touch pad where strain gages are located or where the supporting force can be measured. This requirement may also be incompatible with an airbag deployment doors unless the pad is placed wholly on one flap of the deployment door or multiple pads are used each on a single flap.
The use of a thin piezoelectric polymer film, especially in a finger tapping switch actuation mode, is feasible where the electrical resistance of the film can be controlled and where the signal strength resulting from a finger tap can be measured at the four corners of the touch path. Aside from this possible design, and designs using a matrix or tube structure described below, it is unlikely that surface acoustic wave or other ultrasonic systems will be applicable.
It should be noted that the capacitive touch pad is a technology of choice primarily because of its high resolution in the glove-less mode and the fact that it requires a very light touch to activate.
Although the discussion here has concentrated on the use of touch pad technologies, there are other input technologies that may be usable in some particular applications. In particular, in addition to the touch pad, it will be frequently desirable to place a variety of switches at various points outside of the sensitive area of the touch pad. These switches can be used in a general sense such as buttons that are now on a computer mouse, or they could have dedicated functions such as honking of the horn. Additionally functions of the switches can be set based on the screen that is displayed on the heads up display.
For some implementations, a trackball, joystick, button wheel, or other pointing device may be desirable. Thus, although the preferred embodiment of this invention contemplates using a capacitive or resistance touch pad as the input device, all other input devices, including a keyboard, could be used either in conjunction with the touch pad or, in some cases, as a replacement for the touch pad depending on the particular application or desires of the system designer.
Although the primary focus of this invention has been to develop a heads up display and interactive input devices for location on the steering wheel, in many cases it will be desirable to have other input devices of a similar nature located at other places within the vehicle. For example, an input device location for a passenger may be on the instrument panel, the armrest or attached in an extension and retraction arrangement from any surface of the passenger compartment including the seats, floor, instrument panel, headliner and door. In some cases, the device may be removable from a particular storage location and operated as a hand-held device by either the passenger or the driver. The interface thus can be by hard wire or wireless.
Voice recognition systems are now being applied more and more to vehicles. Such systems are frequently trained on the vehicle operator and can recognize a limited vocabulary sufficient to permit the operator to control many functions of the vehicle by using voice commands. These voice systems are not 100% accurate and heretofore there has been no effective means to provide feedback to the operator of the vehicle indicating what the voice system understood. When used with the heads up display interactive system described herein, a voice-input system can be used either separately or in conjunction with the touch pad systems described herein. In this case, for example, the vehicle operator would see displayed on the heads up display the results of voice commands. If the system misinterpreted the driver's command than a correction can be issued and the process repeated. For example, let us say that the vehicle operator gave a command to the vehicle phone system to dial a specific number. Let us assume that the system misunderstood one of the digits of the number. Without feedback, the driver may not know that he had dialed a wrong number. With feedback he would see the number as it is being dialed displayed on the heads up display and if he or she sees that an error occurred, he or she can issue a command to correct the error. In this manner, the interactive heads up display can function along with a voice command data input system as well as the touch pad systems described herein.
The invention disclosed herein can also be used in conjunction with U.S. Pat. No. 5,829,782, which is included herein by reference, which describes, among other things, the use of an occupant location system to find the approximate location of the mouth of a vehicle operator. Once the location of the mouth has been determined, a directional microphone can focus in on that location and thereby significantly improve the accuracy of voice command systems.
In a similar manner also as described in U.S. Pat. No. 5,822,707, which is included herein by reference, the location of the driver's eyes can be approximately determined and either the seat can be adjusted to place the operators eyes into the eye ellipse, which would be the ideal location for viewing a heads up display or, alternately, the heads up display protection system can be adjusted based on the sensed location of the eyes of the occupant. Although several prior art patents have disclosed the capability of adjusting the heads up display, none of them have done so based on a determination of the location of the eyes of the occupant.
One of the problems with heads up displays as described in the prior art patents is that sometimes the intensity of light coming in from the environment makes it difficult to see the information on the heads up display. In U.S. Pat. No. 5,829,782, a filter is disclosed that can be placed between the eyes of the vehicle operator and the source of external light, headlights or sun, and the windshield can be darkened in an area to filter out the offending light. This concept can be carried further when used with a heads up display to darken the area of the windshield where the heads up display is mounted, or even darken the entire windshield, in order to maintain a sufficient contrast ratio between the light coming from the automatically adjusted heads up display optical system and the light coming from the real world scene. This darkening can be accomplished using electrochromic glass or a liquid crystal system.
An alternate method of communicating with a touch pad or other input device is to do so by passive wireless means. In one implementation of this approach in accordance with the invention, a multi-loop cable is placed around the vehicle and used to inductively charge a circuit located on the touch pad or other input device. The device itself can these be totally free of wires since the information that it sends can also be transmitted wireless to the loop, which now acts as an antenna. The device can now be placed anywhere in the vehicle and in fact it can be moved from place to place without concern for wires. This concept is described in another patent application assigned to the same assignee herein and which is included herein in its entirety by reference.
Although the invention described herein is not limited to a particular heads up display technology, the preferred or best mode technology is to use the garnet crystal heads up system described in U.S. Pat. No. 5,473,466. Although the system has never been applied to automobiles, it has significant advantages over other systems particularly in the resolution and optical intensity areas. The resolution of the garnet crystals as manufactured by Revtek is approximately 600 by 600 pixels. The size of the crystal is typically 1 cm square. Using a laser protection system, a sufficiently large heads up display can be obtained while the system occupies a volume considerably smaller than any system described the prior art. By using a monochromatic laser as the optical source, the energy absorbed by the garnet crystal is kept to a minimum.
These patents are meant to be representative of prior art and not exhaustive. Many other patents that make up the prior art are referenced by the patents reference herein.
All prior art touch systems are active continuously. In the system of this invention, it is contemplated that the heads up display system may only be active or visible when in use. There is no known combination of the prior art that is applicable to this invention.
As the number of functions which the operator must perform while driving the vehicle is increasing, there is a need for a system which will permit the operator to perform various functions related to operating other vehicle systems without requiring him or her to take his or her eyes off of the road.
Such a system will not add undue additional burden to the driver. On the contrary, it will lessen the work load since the driver will not need to take his or her eyes off of the road to control many functions now being performed. On the same basis that people can read road signs while they are driving, people will not have a problem reading messages that are displayed on the heads-up display with the focal point out in front of the vehicle while they are driving, as long as the messages are kept simple. More complicated messages become possible when vehicles are autonomously driven.